Bend-optimized optical fibers have properties adjusted to the purpose of use, especially an adjusted optimization according to the ability to guide light. This includes fibers which are designed to be highly bend sensitive, e. g. sensor fibers in optical bending sensor devices or optical fibers which are designed to be highly bend insensitive, e. g. optical fibers for the transmission of high data rates with a large bandwidth.
Bend-optimized optical fibers usually have a structured radial refractive index profile. This profile includes trench structures, regions with graded refractive index, or complex combinations of several trenches of different widths separated by regions with increased refractive index. It is typically very complicated to produce such fibers with the conventional chemical and/or physical deposition methods, i.e. OVD methods, because the deposition parameters are typically very difficult to reproduce during these OVD methods, especially during plasma outside vapor deposition (POVD). In conventional methods, the most complex refractive index region is deposited in the last process step, which can result in the loss of the complete semifinished product. The semifinished product is also known as a preform.
It remains desirable to have a more reliable method for making bend-optimized optical fibers and improved bend-optimized optical fibers.